Keep-alive electrode for display panel

ABSTRACT

A keep-alive electrode arrangement is intended for use with a display panel which includes a slotted base plate in which a first set of electrodes is seated, with a second set being seated on or in the top surface of the base plate to form an array of first gas-filled cells. An apertured insulating plate is seated on the base plate with the second electrodes therebetween, and third electrodes are seated on the top surface of the second plate. A glass cover plate completes the panel. A keep-alive electrode arrangement comprises first and second electrodes, both seated in one of the slots in the base plate suitably insulated from each other and providing a glow area which is in communication with one of the second electrodes.

United States Patent Caras [541 v KEEP-ALIVE ELECTRODE FOR Primary Examiner-Robert Segal Attorney-Kenneth L. Miller, Robert A. Gree George L. Kensinger and Charles S. Hall DISPLAY PANEL [72] Inventor:

Bernard Caras, Princeton, NJ.

[ 73] Assignee: Burroughs Corporation, Detroit, ABSTRACT I Mlch' A keep-alive electrode arrangement is intended for a March 1, 1971 21 Appl.No.: 119,494

[22] Filed: use with a display panel which includes a slotted base plate in which a first set of electrodes is seated, with a second set being seated on or in the-top surface of the base plate to form an array of first gas-filled cells. An

apertured insulating'plate is seated on the base plate with the second electrodes therebetween, and third electrodes are seated on the top surface of the second 027 nloa 2 1 36 1. 311 8.02. 1 N0 1 8 2 m un w B40." JEN 1" v"6m mun- 0c m m a. S I C .u Smk UIIF HUM 555 plate. A glass cover plate completes the panel. A

[56] Reierehces Cited keep-alive electrode arrangement comprises first and UNITED STATES PATENTS second electrodes, both seated in one of the slots in the base plate suitably insulated from each other and providing a glow area which is in communication with one of the second electrodes.

3,582,979 6/1971 Kupsky..................3l3/220X 2 Claims, 8 Drawing Figures 15% Q /'t A P'A'TEN'TEflncI 11.1912 3.699.376

sum 3 or 3 7256\' I I 256 260A SS v 254 2 INVENTOR. Bernard Cums 1 KEEP-ALIVE ELECTRODE FOR DISPLAY PANEL BACKGROUND OF THE INVENTION One type of display panel now available commercially is known as a SELF-SCAN panel and includes two arrays of cells, a first array of scanning cells, and a second array of display cells. The scanning cells communicate with thedisplay cells, and they are interrelated to provide the desired display of a character or message. The scanning cells are operated column by column and are fired'sequentiallyan'd continuously, and the associated display cells are operated synchronously asdetermined by applied information signals. A set of cells known as reset cells are provided to facilitate the start of each scanning cycle, and, generally a starter arrangement known as a keepalive cell, or cells, is provided to facilitate the initial turn-on of the paneland operation of the reset cells. Keep-alive cells provide first electrons which are necessary to start aglow discharge operation. Various arrang'ements for providing keep-alive cells in display panels of the type described are known and operate successfully. However, as these devices have become smaller and smaller, it has been found necessary to provide new keep-alive arrangements not known in the prior art.

SUMMARY OF THE INVENTION Briefly, the invention comprises providing in the slotted base plate of a SELF-SCAN panel two electrodes seated in the same slot, suitablyinsulated from each other, and providing a supply of electrons or other excited particles for the other cells of the panel.

DESCRIPTION OF THE DRAWINGS FIG. 5 is a sectional, elevational view of a portion of the display panel shown in FIG. 4 at a later stage in its preparation;

FIG. 6 is a sectional, elevational view of a modification of the showing of FIG. 5;

FIG. 7 is a sectional, elevational view of another modification of the invention; and

FIG. 8 is a sectional elevational view of still another modification of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A display panel 10 utilizing the invention includes an insulating base plate of glass, ceramic, or the like. having a plurality of parallel slots 30 formed in the top surface thereof and having an electrode 40, usually operated as a scanning anode, seated in each slot. An array of second electrodes 50, usually operated as scanning cathodes and comprising strips of metal, are seated on or in the top surface of the base plate 20 oriented orthogonally to the first electrodes 40 so that each second electrode crosses each first electrode, and each crossing defines a scanning gas cell 60. The scanning cells are thus arrayed in rows and columns. The cathodes have apertures located at each scanning cell, and, as can be seen, each cathode is aligned with a column of scanning cells. An unapertured cathode 50R, known as a reset cathode, is provided at the left-hand end of the panel ahead of the scanning cathodes 50 and is used to initiate a scanning operation to be described below which is controlled by the scanning cathodes 50.

According to the invention, a keep-alive electrode arrangement is provided in operative relation with the first or reset cathode electrode 50R which is used to start a scanning operation through the array of scanning cells 60. The keep-alive electrode arrangement is seated in a slot 30K in the base plate, and the slot 30K may be between two of the slots 30, or it may lie adjacent to the uppermost or bottommost slot 30. The keep-alive arrangement includes a first wire electrode seated in the slot 30K and of sufficient length to extend beyond the ends of the bottom plate. A layer of insulating material such as a glass frit or the like is placed over the first electrode, with a small opening or discontinuity provided therein exposing a portion of the electrode 80 which lies beneath the reset cathode 50R. A second electrode is seated in the slot 30K on the layer 90 of insulating material, and this second electrode forms the keep-alive cell with electrode 80 through opening 100 in the layer 90 of insulating material. Electrode 110 is coated with an insulating layer except for an opening 124 beneath cathode 50R. One end of the first electrode 80 is removed, and the opposite end of the second electrode 110 is removed, whereby external connection can be made to one wire at one end of the panel and to the other wire at the opposite end. This facilitates the making of connections to two closely spaced electrodes in a small panel.

It is understood that, when-the panel is assembled,

the keep-alive electrodes 80 and 110 are set in place at the same time as the other scanning anodes 40 and before the scanning cathodes 50 are set in place. It is also to be noted that the insulating layers 90 and 120 insulate electrodes 80 and 110 from each other and this material may fill slot 30K but it does not obstruct the space between the cell formed by electrodes 80 and 110 and cathode 50R. Thus, in operation of panel 10, excited particles generated by the keep-alive cell formed by electrodes 80 and 110 can reach reset cathode 50R.

The panel 10 also includesan insulating plate disposed over the cathodes 50, and the cathodes 50 may be seated in slots in the bottom surface of plate 130, if desired. Plate 130 has apertures or display cells arrayed in rows and columns, with each cell 140 being in operative relation with and positioned over a cathode aperture 70 and a scanning cell 60. Display anode wires are disposed on or in the top surface of the insulating plate 130, and each is aligned with a row of display cells 140. A glass cover plate completes the panel.

The various portions of the panel 10 are secured together by means of an air-tight seal formed along the periphery thereof by means of a glass frit or the like. In addition, the panel is filled with the desired gas through a tubulation 180 secured to the base plate 20 and communicating with the interior of the panel through a suitable hole 190 in the base plate 20. The panel may. include any suitable gas such as neon, argon, xenon, etc'., singly or in combination, with a vapor of a metal such as mercury usually included to minimize cathode sputtering. A SELF-SCAN panel preferably uses a Penning gas mixture in which the gases of the mixture have related energy levels such that the metastable atoms of one gas produce ions of the other gas. Neon and xenon comprise a particularly effective Penning mixture. The gas pressure at room temperature is preferably between 50 and 250 Torr, and, 175 Torr has been found to be a convenient pressure.

In operation of the panel, the start of the scanning operation is facilitated by the keep-alive cell made up of the exposed portion of the electrode 80 and the adjacent portion of the second electrode 110. These two electrodes are constantly energized, and the gas cell formed between them is constantly glowing and providing excited particles to facilitate the turn-on of the reset cells formed by the reset cathode 50R and the associated scanning anodes 40 at the beginning of a scanning operation.

The operation of a SELF-SCAN panel is described and claimed in copending application Ser. No. 850,984, filed Aug. 18, 1969. Briefly, the operation comprises applying operating potential to all of the scanning anodes 40 and then applying operating potential sequentially and in turn to each of the scanning cathode electrodes 50, beginning at the left with the reset cathode 50R and proceeding to the right. The proper operation of reset cathode 50R is insured in accordance with the teaching in copending application Ser. No. 881,024, filed Dec. 1, 1969. As each scanning cathode is energized, the associated column of scanning cells 60 is fired, and this operation is carried out sequentially throughout the panel. Simultaneously, with the energization of each cathode 50, information signals are applied to selected display anodes 150, and the display cells 140 associated with the energized anodes 150 and the energized scanning cells 60 are fired. The information signals may change in accordance with the message to be entered, with each scanning cathode energized so that, as the panel is continuously scanned and information signals are entered, a stationary but changeable message made up of energized display cells can be viewed through the face plate.

The keep-alive arrangement described above is particularly suited for use with the type of multi-register display panel described in copending application Ser. No. 21,125, filed Mar. 19, 1970 now US. Pat. No. 3,654,508. The panel described therein includes the same structural features described above except that the slotted base plate and the associated parts are constructed to display a plurality of rows of characters with a space being provided between each row or register of characters. The keep-alive arrangement described above can be conveniently positioned in these slots in the base plate located between character registers.

In a modification of the invention shown in FIG. 4, the keep-alive arrangement comprises a single wire 200 seated in slot 30K in panel base plate but elevated above the base of the slot by any suitable means, for example, by two or more masses 210 of glass which are deposited within and spaced apart along the slot. The ends of the wire 200 extend beyond the ends of plate 20. With the wire 200 supported on the glass masses or mounds 210, it is secured in place by a mass of a glass frit 220 such as Pyroceram which may fill the slot and completely cover all of the wire except for a portion 200 disposed beneath the position to be occupied by the reset cathode. After the wire has been thus secured in place, the exposed portion 200 is cut by means of a knife or chisel-like tool 224 or the like to provide two portions 200A and 2008 (FIG. 5), the adjacent ends of which may be retained as in FIG. 5 or suitably bent as in FIG. 6 to provide the desired spacing between them. The single wire 200 is thus converted to two electrodes which comprise the desired keep-alive cell.

In an alternative arrangement shown in FIG. 7, a shallow depression 230 is formed in slot 30K beneath the position to be occupied by the reset cathode, and the wire 200 is seated at the base of the slot 30K. The wire is secured in place by means of a quantity of glass frit 220, with the uncoated portion 200' thereof overlaying the depression 230. The wire 200 is now divided into two portions 200A and 200B in the manner described above, with the depression providing a space beneath the wire to receive the cutting tool and thus permit it to perform the desired operation.

In still another modification of the invention shown in FIG. 8, the desired keep-alive cell is formed by seating a first elongated wire 240 in slot 30K, with one end 242 extending out of the panel, e.g., at the left-hand end thereof, and with the other end extending along slot 30K. Wire 240 is secured in place with a quantity of insulating material 244, but with a portion 250 of the wire exposed as described above. The wire 240 is bent back upon itself so that the other end 245 extends beyond the left-hand end of slot 30K, and a second quantity of insulating material 256 is deposited in the slot 30K covering all portions of the wire except a portion 260 overlaying the exposed portion 250. The exposed portion 260 is then cut, as represented by the dash lines, to provide two adjacent portions 260A and 2608 which can be suitably mechanically adjusted with respect to each other as described above. There are thus provided two separate wires having ends 242 and 254 accessible at the left-hand end of the panel for applying operating potential thereto.

What is claimed is:

l. A display panel comprising a gas-filled envelope,

an insulating base plate in said envelope having a top surface,

a plurality of parallel first slots formed in said top surface of said base plate,

a first electrode seated in each of said slots,

a plurality of second electrodes seated on the top surface of said base plate disposed parallel to each other and oriented at an angle to said first electrodes whereby each second electrode crosses each first electrode and each such crossing forms a gas cell therewith, said gas cells being in gas communication with each other through said first slots,

a third electrode seated on said top surface of said base plate and spaced from said second electrodes,

said third electrode being in communication with said second electrodes through said slots,

a second slot formed in said top surface of said base plate between two of said first slots,

a keep-alive electrode arrangement, comprising first and second spaced-apart keep-alive electrodes, positioned in said second slot in operative relation with only said third electrode,

said keep-alive electrode arrangement being adapted to be constantly energized to provide excited particles for said third electrode,

said keep-alive electrode arrangement including a single electrode separated into two spaced-apart portions in the vicinity of said third electrode, each of said portions having an end accessible outside said panel for electrical connection thereto,

said two spaced-apart portions being bent at a desired angle and orientation with respect to each other,

said second slot having a base and said single electrode being supported above said base.

2. A display panel comprising a gas-filled envelope,

an insulating base plate in said envelope having a top surface,

a plurality of parallel first slots formed in said top surface of said base plate,

a first electrode seated in each of said slots,

a plurality of second electrodes seated on the top surface of said base plate disposed parallel to each other and oriented at an angle to said first electrodes whereby each second electrode crosses each first electrode and each such crossing forms a gas cell therewith, said gas cells being in gas communication with each other through said first slots,

at third electrode seated on said top surface of said base plate and spaced from said second electrodes, said third electrode being in communication with said second electrodes through said slots,

a second slot formed in said top surface of said base plate between two of said first slots,

a keep-alive electrode arrangement, comprising first and second spaced-apart keep-alive electrodes, positioned in said second slot in operative relation with only said third electrode,

said keep-alive electrode arrangement being adapted to be constantly energized to provide excited particles for said third electrode,

said keep-alive electrode arrangement including a single electrode separated into two spaced-apart portions in the vicinity of said third electrode, each of said portions having an end accessible outside said panel for electrical connection thereto,

said second slot having a base and said single electrode is supported on said base, said base of said second slot having a depression formed therein beneath the portion of said single electrode positioned in the vicinity of said one cathode electrode. 

1. A display panel comprising a gas-filled envelope, an insulating base plate in said envelope having a top surface, a plurality of parallel first slots formed in said top surface of said base plate, a first electrode seated in each of said slots, a plurality of second electrodes seated on the top surface of said base plate disposed parallel to each other and oriented at an angle to said first electrodes whereby each second electrode crosses each first electrode and each such crossing forms a gas cell therewith, said gas cells being in gas communication with each other through said first slots, a third electrode seated on said top surface of said base plate and spaced from said second electrodes, said third electrode being in communication with said second electrodes through said slots, a second slot formed in said top surface of said base plate between two of said first slots, a keep-alive electrode arrangement, comprising first and second spaced-apart keep-alive electrodes, positioned in said second slot in operative relation with only said third electrode, said keep-alive electrode arrangement being adapted to be constantly energized to provide excited particles for said third electrode, said keep-alive electrode arrangement including a single electrode separated into two spaced-apart portions in the vicinity of said third electrode, each of said portions having an end accessible outside said panel for electrical connection thereto, said two spaced-apart portions being bent at a desired angle and orientation with respect to each other, said second slot having a base and said single electrode being supported above said base.
 2. A display panel comprising a gas-filled envelope, an insulating base plate in said envelope having a top surface, a plurality of parallel first slots formed in said top surface of said base plate, a first electrode seated in each of said slots, a plurality of second electrodes seated on the top surface of said base plate disposed parallel to each other and oriented at an angle to said first electrodes whereby each second electrode crosses each first electrode and each such crossing forms a gas cell therewith, said gas cells being in gas communication with each other through said first slots, a third electrode seated on said top surface of said base plate and spaced from said sEcond electrodes, said third electrode being in communication with said second electrodes through said slots, a second slot formed in said top surface of said base plate between two of said first slots, a keep-alive electrode arrangement, comprising first and second spaced-apart keep-alive electrodes, positioned in said second slot in operative relation with only said third electrode, said keep-alive electrode arrangement being adapted to be constantly energized to provide excited particles for said third electrode, said keep-alive electrode arrangement including a single electrode separated into two spaced-apart portions in the vicinity of said third electrode, each of said portions having an end accessible outside said panel for electrical connection thereto, said second slot having a base and said single electrode is supported on said base, said base of said second slot having a depression formed therein beneath the portion of said single electrode positioned in the vicinity of said one cathode electrode. 